Determination of heavy metal levels in Oreochromis niloticus and Chrysichthys nigrodigitatus from Ogun River, Nigeria

Abstract

Comparison of heavy metal levels in Oreochromis niloticus and Chrysichthys nigrodigitatus caught inOgun River (Nigeria) was carried out to reveal the potential health risks associated with fish consumption from the river. Concentrations of copper, lead and cadmium were determined in the gills, eyes, bone, flesh, liver and stomach of the fish species. Ten fish of each species were obtained commercially and analyzed for the metals using Atomic Absorption Spectrophotometer. Data obtained were subjected to one-way analysis of variance (ANOVA) at 5% significant level. The highest concentrations of Cu were observed in the gills of O. niloticus and the eyes followed by liver of C. nigrodigitatus, while the lowest concentrations were detected in the eyes of O. niloticus and bone of C. nigrodigitatus. Lead concentrations were higher in the liver of O. niloticus and gills of C. nigrodigitatus, while the lowest concentrations were detected in stomach of O. niloticus and C. nigrodigitatus respectively. Also, in proximate analysis, composition of dry matter, crude protein, crude fat, ash and carbohydrate contents recorded high in C. nigrodigitatus and O. niloticus and significantly differs. All the metals studied exceeded standard permissible limit for human consumption. Therefore, monitoring of the river is highly recommended, while adequate information, education and training should be strengthened to control further pollution.

Ecological and health risk from heavy metal exposure to fish.

“…This is partly because the gill is naturally endowed with physiological and anatomical properties which must have maximized the absorption efficiency of the heavy metals from the aqueous phase. This is in line with the findings of Eneji et al [16] and Fafioye et al [17] from River Benue and Ogun River respectively. Olusola and Festus [1] opined that gill is the organ that accumulates the highest concentration of metals since it is a metabolically active part, being a dominant site of gas exchange and responsible for acid-base balance, ionic-regulation and nitrogenous waste excretion for fishes (and other aquatic organisms) thereby serving a throng of vital functions for these organisms while Adefemi et al [18] and Eneji et al [16] reported that muscle does not act as an active tissue in the accumulation of metals.…”

Trace Elements in Mollusks, Crustaceans and Fish Commonly Consumed by the Catfish <i>Chrysichthys nigrodigitatus</i> Lacépède, 1803 from the Lake Togo-Lagoon of Aného Hydrosystem (Southern Togo)

“…Overall, the BCF values were higher for Cu, Zn As and Mn. These high accumulations may be due to physiological needs since these elements are essential for the unfolding of biological processes [34] [57] [58] [59]. The significant correlations recorded between the trace elements indicate that these elements come from the same source and that their absorption, distributions and accumulations in each individual would respect the same physicochemical and biological processes [3] [60].…”

Assessment of Piscicidal Potentials of Carica papaya (Linnaeus, 1753) Leaves, Seeds, and Peel Powder on Juveniles of Clarias gariepinus (Burchell, 1822)

“…Piscicidal plants have gained popularity in commercial fishing worldwide, including Nigeria, in recent years [5]. Common piscicidal plants that have been used in harvesting fish by fisherfolks include Tetrapleura tetraptera, Blighia sapida, Raphia vinifera, Parkia biglobosa, and Kigelia africana [6]. The plant parts reported to have piscicidal properties include fruits, seeds, leaves, bark, and roots [6].…”

“…Common piscicidal plants that have been used in harvesting fish by fisherfolks include Tetrapleura tetraptera, Blighia sapida, Raphia vinifera, Parkia biglobosa, and Kigelia africana [6]. The plant parts reported to have piscicidal properties include fruits, seeds, leaves, bark, and roots [6]. Also, the active ingredients in the plant parts are said to have different capacities in harvesting fish, and the mode of action depends on the methods of application, which could be directly in the form of aqueous extract, powder, or dissolved in alcohol [7].…”